Concentric band high pressure forming chambers



July 2, 1968 F. J. FUCHS, JR 3,390,563

CONCENTRIC BAND HIGH PRESSURE FORMING CHAMBERS i 2L W i 2/ M a: x/ ,M

l V a; d; a &\\\\\ E J. FUCHS, JR.

A TTOR/VE'Y July 2, 1968 F. J. FUCHS, JR 3,390,563

CONCENTRIC. BAND HIGH PRESSURE FORMING CHAMBERS Filed Dec. 9. 1965 2 Sheets-Sheet FIG. 2

United States Patent Office Patented July 2, 1968 3,390,563 1 CONCENTRIC BAND HIGH PRESSURE FORMING CHAMBERS Francis J. Fuchs, Jr., Princeton Junction, N.I., assignor to Western Electric Company, Inc., New York, N.Y., a

corporation of New York Filed Dec. 9, 1965, Ser. No. 512,641 7 Claims. (Cl. 72-60) This invention relates to concentric band high pressure forming chambers and more particularly to a high pressure forming chamber wherein a plurality of concentr c bands are rendered successively effective, from the outer band to the inner, to absorb increasing pressures imparted to shape a workpiece positioned within the chamber.

It is known that metal stock can be more easily shaped and formed when subjected to ultrahigh pressures which are eifective to change the ductile characteristics of the metal. These high pressures can only be generated within special chambers having facilitiesto compensate for the high pressures. High pressured chambers may be constructed by helically winding one or more bands upon each other without intermediate spacing, resulting in the consumation of large amounts of metal. In this arrangement, the high pressures generated within the chamber are successively taken up by the inner band or convolution and then by each succeeding convolution resulting in the subjection of the first convolution to excessively high tension stresses.

Further, high pressure vessels may be constructed by providing a succession of concentric but spaced cylinders and then introducing pressurized fluid into the spaces to compensate for the increasing high pressures encountered within a centrally located forming cylinder. In this arrangement, the effective operation is dependent upon the availability and flow of pressurized fluid into the spaces.

An object of this invention resides in a new and improved concentric band high pressure forming chamber.

Another object resides in a forming chamber having a plurality of concentric bands arranged and constructed to successively absorb, from the outer band to the inner band, pressures generated within the forming chamber.

A further object of the invention is the provision of a multi-band high pressure vessel wherein each band has teeth formed on opposite sides and at opposite ends, which teeth mesh and move into successive interlocking engagement as pressure in the chamber is progressively increased.

-With these and other objects in view, the present invention contemplates a plurality of concentric bands mounted to provide a high pressure forming chamber wherein pressures generated within the chambers impart expanding tension forces to each successive band progressing inwardly from the outer band. More particularly, each band comprises successively smaller lengths of sheet metal having oppositely tapered ends on which teeth are formed. Each band is bent to form a ring so that teeth on the opposite ends are positioned in a meshing relationship. Each succeeding outer band compresses the preceding inner band to provide successively increasing gaps or spaces between the teeth. As the pressure builds up in the chamber, the initial load in the form of hoop tensile stresses is taken up by the outer band which expands to allow the next preceding inner band to expand and move the teeth on this band into interlocking engagement to absorb the increased expanding pressure load. The bands are thus successively rendered effective progressing from the outer to the inner band to take up the increases in pressure generated within the chamber.

Other objects and advantages of the present invention will be apparent upon consideration of the following detailed description when considered in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevational view, partially in section, showing a high pressure forming chamber embodying the principles of the present invention;

FIG. 2 is a cross sectional view taken along line 2-2 of FIG. 1 illustrating an arrangement of concentric toothed bands surrounding the high pressure forming chamber;

FIG. 3 is a top plan view of one toothed band that may be bent to form one of the concentric bands; and

FIG. 4 is a greatly enlarged view of one of the inner bands particularly illustrating the spacing between the teeth formed on opposite sides and ends of the band.

Referring to FIG. 1, there is shown a billet 10 of metal which is to be shaped by subjection to high pressures in a chamber 11. The billet may be extruded or shaped through an extrusion orifice 12. When certain metals such as copper, steel, etc. are subjected to ultra-high pressures, their ductile characteristics improve to permit more facile shaping. This increased ductility allows for a more uniform plastic flow of the metal, thus, permitting the shaping of articles that heretofore were not considered suitable for pressure forming.

The chamber 11 comprises an inner sleeve 13 surrounded by a plurality of concentric bands 16, 17, and 18 which are rendered effective, from the outer to the inner, to successively take up increases in pressure generated within the chamber 11. The sleeve and bands are supported between a lower plate 20 and an upper plate 19 held together by four or more tie bolts 21. The upper plate 19 is provided with a small downwardly projecting hub 22 which engages a seal 23 meshing against the top of the sleeve 13. The outer portion of the hub may also abut a small portion of the top edge of the band 16. With this hub construction, there is provided a space 24 between the bottom of the top plate 19 and the top edges of the bands which permits the bands to radially expand. The top plate 19 is provided with a bore 26 which extends through the hub 22 into the chamber 11. Slidably mounted within this bore is a. piston 28 projecting from a high pressure cylinder 29.

Attention is directed to the lower plate 20 which is provided with a bore 31 to receive a support standard 32 mounted on a bolster plate 33. Plate 20 may be forcefitted or otherwise secured to the standard 32 so that the lower plate supports the over-all forming chamber. A second ring-like seal 36 is interposed between the plate 20 and the sleeve 13 to preclude the exit of forming fluid from the chamber 11.

The extrusion orifice 12 formed in the standard 32 extends through a necked-down portion of a bore 37 drilled through the standard. Slidably mounted within the bore 37 is a piston 38 extending from a high pressure fluid cylinder 39. A seal 41 is fitted in a circumferential slot machined in the wall of the bore 37. The chamber formed by the bore 37 and the piston 38 is filled with fluid which is pressurized and serves to receive the ex truded billet 10.

Considering now a construction of the bands 16, -17, and 18 with particular reference to FIGS. 2, 3, and 4, it will be noted that each band, such as band 16, when in a straight line position (see FIG. 3) is in eifect rhornboidal in shape, that is, the band has a pair of parallel smooth sides 42 and 43 and adjacent toothed tapered sides 44 and 46 that are at oblique angles to the parallel sides. The toothed sides have right-angular teeth 47 and 48. The teeth may also be of a different shape, provided that, when the band is bent into a ring and the teeth are fitted into each other, there will be gaps between the sides of the teeth. The teeth in this instance should be of sufiicient length so that the top of each tooth engages the bottom of the space between the pair of teeth into which the tooth is fitted.

In the illustrated embodiment, as best shown in FIG. 4,

3 the hypotenuse 49 of a tooth 47 abuts the hypotenuse 51 of a tooth 48. When the teeth are fitted together, a space 52 will exist between corresponding sides 53 and 54 of adjacent teeth 47 and 48.

Consider now that the bending of the bands 16, 17, and 18 to form concentric rings, attention is directed particularly to FIG. 2 where it is shown that the teeth on the outer band 18 are force fitted into meshing engagement so that there is no space between the teeth. The natural resilience of the metallic band 18 maintains this force fit meshing engagement of the teeth. The outer ring 18 may also be constructed as a continuous band without the toothed construction. The next succeeding inner band 17 is selected to be of a length sufficient to be compressed by the outer band 18. In this instance, with the band 17 formed in a ring and compressed to a diameter less than it would be if the band was not constrained by the outer band 18, there is a gap 52' between adjacent fitted teeth. In a like manner, the band 16 is selected to be of a length so as to be constrained by the band 17 to provide a gap 53 which is larger than the gap 52'.

Considering now the over-all operation, the piston 28 is Withdrawn from the chamber 11 and a billet is placed over the orifice 12 on the standard 32. The chamber 11 is filled with fluid and the cylinder 29 receives high pressure fluid to force the piston 28 down into the chamber 11. As the piston 28 moves into the chamber 11, high pressure fluid is also admitted to the cylinder 39 to advance the piston 38 to pressurize the fluid within the bore 37. The pressure builds up in the chamber 11 to act on the billet 10 and extrude the billet through the orifice 12. The pressurized fluid in the chamber 11 is of a magnitude sufficient to change the ductile characteristics of the billet 10; hence, facilitating the extrusion through the orifice 12. The pressurized fluid within the bore 37 opposes the extrusion and prevents the extrusion of the billet until the pressure within the chamber 1 1 is built up to a range necessary to render the billet 10 ductile. These pressures are of tremendous magnitude and may be from 300,000 p.s.i. to an excess of 1,000,000 p.s.i. depending upon the pressure necessary to render the billet ductile.

This build up of pressurized fluid exerts radial forces on the sleeve 13 to expand this sleeve and in a like manner expand the bands 16, '17, and 18. Inasmuch as there are gaps between the teeth on the bands 16 and 17, these bands readily expand so that the initial load is taken up by the outer band 18. As the bands 16 and 17 expand, the respective hypotenuse on the teeth rub against each other to take up some of the expansion force. The band 18 expands to such a degree that the teeth on the band 17 move into abutting engagement, so that now the band 17 absorbs a large portion of the expansion forces. Further, build up of pressure within the chamber 11 results in an expansion of the band 16 until such time as the gap 52 between the teeth is taken up and the teeth abut each other to take up the expansion forces. At this time, all the bands 16, 17, and 18 are functioning to absorb the radial forces emanating from the chamber 11. With this successive assumption of the expansion forces by the bands 18, 17, and then 16, the hoop tensile stresses in the various bands may be maintained substantially equal or at any desired ratio. As the pressure imparted to the fluid within the chamber 11 approaches the ductile range, the pressurized fluid Within the cylinder 39 may be relieved to reduce the pressure on the fluid in the bore 37 and, thus, facilitate the extrusion of the billet 10 into the bore 37. Upon completion of the extrusion, piston 28 is withdrawn to relieve the pressure within the chamber 11 and the piston 38 is withdrawn to allow the removal of the shaped billet from the bore 37.

It is to be understood that the above-described arrangements of apparatus and construction of elemental parts such as the number of concentric bands 16, 17, and 18 are simply illustrative of an application of the principles of the invention and many other modifications may be made without departing from the invention.

What is claimed is:

1. In a high pressure vessel,

a plurality of concentric bands, and

means on each band for rendering said bands effective successively from the outer band to the inner band, for absorbing radially outwardly expanding forces emanating from the center of the vessel.

2. In a high pressure forming vessel wherein the wall comprises,

concentric bands each of which is rhomboidal in cross section having parallel sides and adjacent oblique angular sides, and

teeth formed on each oblique side to interfit with the teeth on the opposite oblique side to maintain the parallel sides into an array of concentric bands.

3. In a high pressure forming vessel as defined in claim 2 wherein the teeth on each band are of a right angular configuration with the hypotenuse of each tooth on each oblique side abutting the hypotenuse of a tooth on the opposite oblique side.

4. In a high pressure vessel,

a first wall member comprising a band having opposed tapered ends,

first teeth formed on each tapered end and interlocking with each other to form the band into a circle,

a second wall member comprising a second hand having opposed ends and concentrically positioned around said first band, and

second teeth formed on each tapered end of said second band and interfitted with each other to form said second hand into a circle which compresses the first band to form spaces between the teeth on said first band.

5. In a vessel for a high pressure forming press,

an inner sleeve defining the forming chamber,

an outer concentric band spaced from said sleeve,

said band having teeth formed on opposite ends and positioned to mesh with each other,

a plurality of additional concentric bands interposed between said sleeve and said outer band,

each of said bands having teeth formed on opposite ends to mesh with each other, and

each of said bands from the outer to the inner being of successively smaller lengths that each succeeding band is compressed to provide successively increasing series of gaps between the meshing teeth of each band.

6. In a high pressure forming chamber,

a plurality of concentric bands having overlapping ends,

each of said overlapping ends having a set of meshing teeth,

an outer band for compressing said concentric bands to form successively increasing gaps between each set of teeth on each succeeding band, and

means for applying a radially expanding force to the inner concentric band to successively expand said concentric bands and move each succeeding set of teeth into engagement.

7. A pressure vessel comprising:

an outer band;

a plurality of concentrically arranged, radially outwardly expandable bands;

said outer band surrounding said plurality of bands;

each band of said plurality provided with means for limiting the radially outward expansion thereof;

each band for constricting the next adjacent radially inward band below its radially outward expandable limit; and

the length of each band of said plurality predetermined such that, upon the radially outward expansion of said bands of said plurality, such bands expand to 5 their respective radially outward limits successively 2,284,761 radially inwardly. 2,326,176 2,964,209 References Cited 2,984,379

UNITED STATES PATENTS 5 1,696,725 12/1928 Murray. 1,958,582 5/1934 Kerr. 2,253,093 8/1941 Raichle. 2,273,736 2/1942 Raymond.

6 Nathan. Schierenbeck. Eddy. Borzsei et a1. 220-3 Hahn et al. Pechacek 220-3 CHARLES W. LANHAM, Primary Examiner. K. C. DECKER, Assistant Examiner. 

5. IN A VESSEL FOR A HIGH PRESSURE FORMING PRESS, AN INNER SLEEVE DEFINING THE FORMING CHAMBER, AN OUTER CONCENTRIC BAND SPACED FROM SAID SLEEVE, SAID BAND HAVING TEETH FORMED ON OPPOSITE ENDS AND POSITIONED TO MESH WITH EACH OTHER, A PLURALITY OF ADDITIONAL CONCENTRIC BANDS INTERPOSED BETWEEN SAID SLEEVER AND SAID OUTER BAND, EACH OF SAID BANDS HAVING TEETH FORMED ON OPPOSITE ENDS TO MESH WITH EACH OTHER, AND EACH OF SAID BANDS FROM THE OUTER TO THE INNER BEING OF SUCCESSIVELY SMALLER LENGTHS THAT EACH SUCCEEDING BAND IS COMPRESSED TO PROVIDED SUCCESSIVELY INCREASING SERIES OF GAPS BETWEEN THE MESHING TEETH OF EACH BAND. 